JP2795898B2 - Method for manufacturing MSI type nonlinear switching element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] Liquid crystal display elements are widely applied as flat panel displays with low power consumption. Among them, an active matrix system in which a switching element is formed in each pixel and driven is being used as a large-capacity, high-quality display element in televisions, information terminals, and the like. 3 for switching element
Terminal type TFTs (thin film transistors) and two-terminal type diodes and non-linear resistance elements such as MIM and MSI (metal semi-insulator) are used. Commercialization was preceded by three-terminal TFTs, but two-terminal TFTs are easier to manufacture than three-terminal TFTs, and are expected to grow in the future.

The present invention relates to an MSI (metal semi-insulator) type nonlinear switching element.

[Conventional technology and its problems]

FIG. 2 shows a conventional MSI type nonlinear switching element. A first electrode layer 2 made of a transparent electrode such as ITO (indium oxide) is formed and patterned on a substrate 1 such as glass.
Subsequently, a semi-insulating layer 3 such as non-stoichiometric SiNx or SiNxOy is formed and patterned. Finally, a second electrode layer 5 of Cr, Al, or the like is formed and patterned.

The problem of the conventional example is that the manufacturing process is slightly complicated.
In the conventional example of FIG. 2, three photomasks are required. Further, since the first electrode layer 2 and the second electrode layer 5 are clearly exposed, a leak current through the path 21 in the drawing tends to make the OFF characteristic as a switching element unstable.

An object of the present invention is to provide a method for simplifying and stabilizing the conventional manufacturing method.

[Means for solving the problem]

The present invention relates to a method of manufacturing an MSI type nonlinear switching element, wherein a first electrode layer and a semi-insulating layer are continuously formed on a substrate.
Patterning, oxidizing the first electrode layer to form an oxide film, and providing a second electrode layer on the first electrode layer and the oxide film. 2. A stable MSI type nonlinear switching element can be manufactured by a two-mask process.

〔Example〕

FIG. 1 is a sectional view showing a method for manufacturing an MSI type nonlinear switching element according to an embodiment of the present invention.

FIG. 1A shows a step of continuously forming and patterning a first electrode layer 2 and a semi-insulating layer 3 on a substrate 1. The first electrode layer 2 is a substantially oxidizable metal, specifically, Ta,
Al, Mo, MoSix, etc. are formed by sputtering or vapor deposition. The semi-insulating layer 3 is a thin film having a non-linear resistance characteristic of 20 to 150 nm, such as non-stoichiometric SiNx, SiOxNy, etc.
And the like.

FIG. 1B shows a step of oxidizing the first electrode layer 2 to form an oxide film 4.

As a first embodiment of the method of forming the oxide film 4 by oxidizing the first electrode layer 2, anodic oxidation is used. For example, when Ta, Al, MoSix, or the like is used as the first electrode layer, the thickness is about 100 to 500 nm by anodizing in a citric acid solution.
Is formed on the side wall of the first electrode layer 2 as shown in FIG.

As a second embodiment of the method of forming the oxide film 4 by oxidizing the first electrode layer 2, thermal oxidation is used. For example, the first
When Ta, Mo or the like is used as the electrode layer 2 of FIG. So first
Is formed on the side wall of the electrode layer 2.

FIG. 1C shows a step of forming and patterning a second electrode layer 5 on the first electrode layer 2 and the oxide film 4. In the case of a transmissive display, a transparent electrode is preferable as the second electrode, and a transparent electrode such as ITO (indium oxide) may be used. In the reflection type, a reflection electrode made of a metal such as Al, Cr, and Au may be used.

A first feature of the present invention is that the conventional example requires three photomasks and three patterning steps, whereas two photomasks and two patterning steps have no problem. .
The present invention has significant advantages in terms of manufacturing equipment investment, manufacturing yield, and manufacturing cost.

A second feature of the present invention is that the surface of the first electrode layer 2 is not finally exposed, and there is no leak path as shown in FIG. Since the entire surface of the first electrode layer 2 is covered with the oxide film 4, the surface is less affected by moisture and the like, and is extremely stable as compared with the conventional example.

〔The invention's effect〕

As is clear from the above embodiments, the present invention makes it possible to manufacture an MSI type nonlinear switching element which is very stable as compared with the conventional example, by a very simple process of a two-mask process.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a method of manufacturing an MSI type nonlinear switching element according to an embodiment of the present invention, and FIG.
It is sectional drawing which shows the manufacturing method of an I-type nonlinear switching element. DESCRIPTION OF SYMBOLS 1 ... board | substrate, 2 ... 1st electrode layer, 3 ... semi-insulating layer, 4 ... oxide film, 5 ... 2nd electrode layer.

Claims (4)

(57) [Claims] 1. A semiconductor device comprising: a first electrode layer and a second electrode layer provided on a substrate; and a semi-insulating layer provided between the two electrode layers.
In a method for manufacturing an MSI (metal semi-insulator) type nonlinear switching element, a step of continuously forming and patterning a first electrode layer and a semi-insulating layer on a substrate; A method for manufacturing an MSI nonlinear switching element, comprising: oxidizing to form an oxide film; and providing a first electrode layer and a second electrode layer on the oxide film. 2. The method for manufacturing an MSI type nonlinear switching element according to claim 1, wherein the first electrode layer is oxidized by anodic oxidation. 3. The method according to claim 1, wherein the method of oxidizing the first electrode layer is thermal oxidation. 4. The method according to claim 1, wherein the first electrode layer is a Ta film.